Sub Floor Ventilation – How Does It Work?


It’s funny you do everything you can to ensure your home is draft proof and well insulated and yet the walls and floor still need ventilation!

You may wonder why this is the case and whether you really need it, the answer is you do.


The purpose of Sub Floor Ventilation

Damp and moisture are two of the biggest enemies of any house. Left untreated they can encourage the growth of fungi and even the reproduction of bacteria. This can have a detrimental effect on your health.

You may notice the fungi or mold growing on your walls and the floor or you may notice the damp smell first. If you find these symptoms of moisture you need to act quickly.

But that’s not the only issue you can face with inadequate ventilation. The moisture attracts insects and other pests. They need somewhere warm, moist and with a food supply. A damp house provides all three of these things.

Unfortunately the pests can quickly multiple and bring bacteria and disease into your home. They can also eat into your foundation or the structure of your home potentially damaging it beyond repair.

How Does The Sub Floor Ventilation System Work?

Any country which has frequent severe storms should encourage all homeowners to purchase a reputable sub floor ventilation system. This is because storms make the ground wet and this will soak under your hoe; beneath the foundations.

The damp will then travel upwards and can potentially get into your home. Of course a good damp proof course and damp proof membrane should help to prevent moisture getting into your home but these membranes do deteriorate over time.

Although there are several different kinds of sub floor ventilation systems the principle by which they all work is the same.

You will need two holes cut into the sides of your sub floor. One of these will be an entry hole for air; the other the exit point. Air going into the sub floor space should be fresh and dry; the damp air is pushed out the other hole.

In the sub floor space there will be an air extraction unit. This is electrically powered and sits on the floor; extracting moisture from the floor. A fan is built into this unit which creates a negative pressure under your house. This forces air to come in the one way vent; at the same time air is pushed out the other vent by the unit; with the moisture in it.

It is essential to note that the air coming into the sub floor should be dry. That’s why it is best to run the unit during the middle of the day; when the air is driest. It is possible to purchase a pump that will suck the air in from outside; increasing the flow rate and potentially drying the sub floor faster.

You can wire the unit into your home electrics but you may prefer to invest in a solar panel and run the unit this way; this will ensure there are no ongoing costs for you to worry about.